The present invention relates to a system (observation system, control system, etc.) constructed using a plurality of sensing data, or in particular to an exhaust gas diagnosis system and a vehicle control system for automotive vehicles.
The recent progress of the computerized vehicle control operation has increased the number of microcomputers mounted on a vehicle to more than several tens and also the number of sensors connected thereto. The microcomputers are mounted for the body system, the information system, the drive control system, the steering control system and the power train system of the vehicle to realize a finely detailed control operation and an improved operability. The communication between these microcomputers and between the microcomputers and the sensors is carried out by cables, and the weight of the wire harnesses (wires and connectors) used for this configuration exceeds several tens of kg. Also, the space for wiring in the vehicle is so limited that the wiring space to add new functions has become more and more difficult to secure.
In addition, what is called the X-by-wire technique for reducing the mechanical components of the vehicle has made a progress and come to replace the conventional mechanical and hydraulic control systems to such an extent that the vehicle is now controlled substantially by a combination of a motor and an electronic control unit. To realize the X-by-wire system, an improved reliability is indispensable, and with regard to the electronic control system, the current trend is toward securing the reliability by double or triple system configuration. This trend of the X-by-wire technique also increases the wire harnesses of the automotive vehicle, leading to an even more increased wire harness mass.
To reduce the weight and the fuel consumption of the vehicle by weight reduction, therefore, the wire harness is required to be reduced or the quantity of the wire harness is required to be prevented from increasing. The wire harness may be reduced by radio data communication, and an example thereof is disclosed in JP-A-2003-002019 (Patent Document 1) involving a tire air pressure monitor. Since each tire is rotating, a tire air pressure sensor mounted on the tire valve, etc. and a tire air pressure monitor control unit to monitor the state of the air pressure sensor mounted on the vehicle cannot be directly connected by cable to each other. In the system disclosed in Patent Document 1, a radio communication repeater is arranged on the tire wheel to realize the radio communication, and data are transmitted by radio communication between the tire air pressure sensor and the radio communication repeaters. This radio communication realizes the communication with the rotary component parts.